glGo supports a mark for the last move and a couple of common SGF marks like square, triangles, letters etc.
There are two markers available for the last move mark:
Simple marks appear very similar to the Java version. A plain circle is drawn on the stone - actually it is drawn inside the stone to avoid odd effects when rotating the board.
The SGF marks like square, triangle, circle and cross marks are always drawn as simple marks.
Multitextures are an extension to OpenGL and is only available when running in hardware mode. Most graphic cards should support multitextures. Multitextures means, a second texture can be laid over the stone. The white stones already have the grain texture, multitexture allows to add a second texture with a mark. This makes the marks look realistic, as if painted over the stone, and not floating above or inside the stone as the simple marks do. I intentionally made a mark texture which looks "as if painted", instead of the usual plain circle or cross. I think this looks pretty realistic. There is currently one problem with these marks, when zooming in closely and rotating, the marks slide over the stone. This has to be improved.
glGo will detect if your graphic card supports multitextures and enable this feature. If it is not supported, multitexture marks are automatically disabled.